Hydrocracking catalyst and process for hydrocracking shale oils



United States Patent HYDROCRACKING CATALYST AND PROCESS FOR HYDROCRACKING SHALE OILS Clark Edward Adams and Charles Newton Kimberlin, Jr., Baton Rouge, La., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Dec. 17, 1958, Ser. No. 780,960

7 Claims. or. 208-111) The present invention relates .to the conversion of higher boiling hydrocarbons to lower boiling materials by hydrocracking as well as to certain new catalyst compositions which are advantageously used in said conversion. More particularly, this invention pertains to a catalyst and process for hydrocracking raw shale oil, shale oil distillates and coker gas oils as well as ordinary gas oil to produce lower-boiling, useful products.

It is well known to the art that various high boiling hydrocarbons or mixtures of hydrocarbons can be converted to useful lower boiling products by cracking, with or without catalysts, at temperatures of about 800ll00 F. If this conversion is effected under a substantial hydrogen partial pressure, the process may be carried out at lower temperatures and is called hydrocracking. The latter is an important refinery tool particularly insofar as it is effective in forming valuable products from high sulfurand nitrogen-containing heavy hydrocarbonssuch as shale oil and high sulfur crude oils.

Raw shale oil'is obtained by retorting oil shale and contains hydrocarbons and organic material consisting of hydrocarbons in combination with sulfur, nitrogen, and oxygen. The shale oil has an extremely high content ofv nitrogen compounds which distinguishes it from crude petroleum oil. Various procedures have been suggested for refining shale oil or various fractions separated from shale oil. Conventional methods for refining or conversion are not applicable to shale oil because of excessive carbon or coke formation. This is ordinarily attributed to the nitrogen, sulfur and/or oxygen present in the oil feed. In addition, the gasoline product usually contains excessive amounts of sulfur and requires'further refining. In order to eliminate these undesirable compounds and prepare a stock suitable for cracking or further refining, it has been felt necessary to resort to coking or hydrogenation of the shale oil. Hydrogenation is an expensive-operation in view of .the high pressure and expensive equipment necessary and accordingly this method of processing shale oil is not competitive with processing of crude petroleum oil.

It has now been found that catalysts consisting of molybdenum oxide and/or cobalt molybdate deposited upon an alumina-boria support are highly effective in upgrading refractory feeds such as shale oil, shale oil distillates as well as gas oil and whole crudes containing large quantities of sulfur and/or nitrogen. Conversion to valuable end products as well as to intermediate products that may be readily upgraded further, as by merely hydroforming to high octane number, clean burning motor gasoline is effected under hydrocracking conditions at about 850-ll00 F., preferably at about 900-1000 F. at pressures of about 100 to 1000 p.s.i.g. and with 1000 to 10,000 s.c.f. of hydrogen or hydrogen-rich recycle gas charged per barrel of liquid feed.

The catalysts in accordance with the present invention comprise from about to 20 wt. percent of molybdenum oxide, or cobalt molybdate deposited upon an aluminaboria support comprising 80 to 95 wt. percent of alumina and 5 to 20 wt. percent of boron oxide. If desired, the support material may also contain minor amounts (about 2 to ance with the present invention will have an initial boiling zssaaat 2 at most 10 wt. percent of silica as a stabilizer). Accordingly the analysis of the catalysts in accordance with the present invention is as follows:

.l000-1200 F. for 2 to 16 hours.

Range, Wt. Preferred,

Percent Wt. Percent The catalysts can be prepared in various ways. For example, boric acid can be intermixed with activated alumina or a suitable activated alumina precursor such as alumina hydrogel, alpha alumina trihydrate, beta alumina trihydrate or alpha alumina monohydrate, and then drying at about ZOO-250 F. and calcining at about If desired, small amounts of silica can be incorporated with the alumina as by mixing a silica hydrogel with the alumina hydrogel or by precipitating hydrous silica from sodium silicate or other silica producing compound along with the hydrated alumina.

The molybdenum oxide or the molybdenum oxide and cobalt oxide are then incorporated into the alumina-boria or aluminasilica boria support material. For example, molybdenum oxide in vaporous or finely dividedform is contacted with the support material at elevated temperatures or the support may be impregnated with a suitable molybdenum compound such as ammonium molybdate or has been applied this term is intended to include catalysts in which the cobalt oxide and the molybdenum oxides are chemically combined as well as to various mixtures of cobalt oxide and molybdenum oxide.

The catalysts in accordance with the present invention are especially adapted for the hydrocracking of refractory cracking stocks, particularly those containing large quantities of sulfur, nitrogen, and/or oxygen. Such stocks include raw shale oil, shale oil distillates, tar sand bitumen, coker gas oil, and regular gas oil. The sulfur content of the feedstock may vary from about 0.2 wt. percent for a low sulfur gas oil to as high as 4 wt. percent for a high sulfur gas oil. The nitrogen content of a shale oil feedstock may vary between about 1 and 3 wt. percent.

The sulfur content of a shale oil feed may vary between about 0.2 and 1.5 wt. percent. The gasoline product from or without acid washing by a simple hydroforming treatment with molybdenum oxide or platinum catalysts under known conditions. Such a combination treatment is especially valuable since the make gas from the hydroforming treatment can be used advantageously to supply the hydrogen required in the hydrocracking treatment.

The feedstocks subjected to hydrocracking in accorddrawn from the conversion reactor and transferred to a regenerator where the inactivating deposits are burned 011.

The temperature in the hydrocracking reaction or conversion is in the range of from about 800 to 1100 F., preferably about 900 to 1000 F., and the pressure is from about 100 to 1000 p.s.i.g., preferably about 650- 750 p.s.i.g. Hydrogen or hydrogen-rich recycle gas is charged to the hydrocracking conversion zone at a rate of from about 1000 to 10,000 s.c.f. per barrel of liquid feed. The oil feed rate is from about 0.1 to 10 parts by weight of oil per hour per part by Weight of catalyst in the hydrocracking conversion zone. Regeneration of the catalyst can be effective by contact with hydrogen in the absence of oil feed at or above reaction temperatures for suitable periods or by burning off the inactivating deposits with an oxygen-containing gas or air at temperatures of about 1000 to 1200" F. The regenerated catalyst is desirably stripped with nitrogen or other inert stripping gas such as steam and then with hydrogen prior to further use thereof in hydrocracking.

The following examples are illustrative of the present invention.

EXAMPLE 1 A cobalt molybdate on alumina boria catalyst was prepared by impregnating a commercial activated alumina (Alcoa H44) with a mixture of cobalt acetate and ammonium molybdate in water to give 15% CoMoO on the alumina. The resulting catalyst was dried and calcined for 6 hours at 1200 F. This catalyst was then impregnated with a boric acid solution to give 10% B on the catalyst. Composition: 10% B 0 13.5% CQMOO4 and A1203.

The foregoing catalyst designated Catalyst A was thereupon tested to compare its hydrocracking efiicacy with that of several other hydrocracking and cracking catalysts designated as Catalysts B, C, D, E, and F. Catalyst B was a commercial hydroforming catalyst comprising 0.6 wt. percent platinum supported upon eta alumina obtained from aluminum alcoholate. Catalyst C contained 0.3 wt. percent of platinum on an activated alumina support. Catalyst D was a commercial silicaalumina cracking catalyst containing about 13% A1 0 Catalyst E contained 0.1% platinum impregnated upon the commercial silica-alumina cracking catalyst (Catalyst D). Catalyst F was a mixture of four parts of the commercial silica alumina cracking catalyst (Catalyst D) with one part of the commercial hydroforming cata-, lyst (Catalyst B). Each of the foregoing catalysts was used to hydrocrack raw shale oil feed boiling above 400 F. with a gravity of 206 API and containing 1.9 wt. percent N and 0.7 Wt. percent S. Reaction conditions in each case were 900 F. reactor temperature, 700 p.s.i.g., 1 v./v./hr., and with 5000 s.c.f. H /B. The results obtained are summarized in Table I.

Table I Catalyst. A B o D E F- Gonversion (400 F.), Percent.-- 62 44 33 44 54 50 Yields:

(J -400 F.. Vol. Percent"; 52 39 30 30 40 39 Cr, Wt. Percent 15 11 8 11 12 11 Coke, Wt. Percent 6.0 4. 5.3 12. 4 7.0 10. 4

These results show the marked superiority of the catalyst of the present invention over a variety of other cracking or hydrocracking catalysts for the conversion of raw shale oil to motor gasoline.

EXAMPLE 2 Catalyst A of Example 1 in accordance with the present invention was again tested for the hydrocracking of a raw shale oil in comparison with a Catalyst G which contained 3.9% C00 and 12.8% M00 distributed upon an activated alumina support, a catalyst H which was an alumina boria cracking catalyst containing 20% boria, and Catalyst I which was prepared by incorporating 15% cobalt molybdate on a synthetic silica-alumina cracking catalyst (13% Al O -87% SiO The reaction conditions were the same as in Example 1 and the run time was one hour. The results are summarized in Table H.

Table II Catalyst A G I H I I Conversion (400 F.), Vol. Percent.-- 66 57 69 52 Yields:

Ct-400 F., Vol. Percent 63 54 56 47 0 Gas, Wt. Percent. 15 13 10 13 Carbon. Wt. PercentL. 6. 0 4. 5 13.1 5. 4 Wt. Percent Nitrogen 400 F.+ 0. 13 0. 19 0. 9S

Product distribution was similar from the two cobalt molybdate catalysts A and G. However, addition of boria in accordance with the present invention imparts a substantial increase in activity to Catalyst A. While the boria-alumina cracking Catalyst H had a slightly- A cobalt molybdate-boria-alumina catalyst in accordance with the present invenion was compared with a cobalt molybdate on alumina catalyst for hydrocracking a Tia Juana coker gas oil. The coker gas oil was prepared by fluid coking the 30% bottoms from Tia Juana Medium Crude with recycle of the 1000 F.+ product. The

430 F.+ gas oil was obtained in about 50% yield and had a gravity of 19.8 API and a sulfur content of 2.0 wt. percent.

The reaction conditions and the results obtained on hydrocracking this gas oil are summarized in Table III.

Table III HYDROCRACKING OF TIA JUANA COKER GAS OIL 700 P.S.I.G., 5500-7500 S.C.F./B. OF H: AND 1 HOUR CYCLES Catalyst COMOOrIBzOaiAizOa COMOO-tIAlzOs Temperature, F 938 880 923 85 V./V./Hr 0.87 0. 0.77 0. 89 430 F. Conv. Vol. Percent; 90. 6 76. 4 64. 6 37. 7 Yields:

Carbon, Wt. Percent (8. 2) (3. 9) (4. 4) (4. 8) 24.9 16.4 13.6 7.5 21. 8 20. l 5. 2 1. 5

cent 64.1 55. 0 53. 2 31. 0 R.O.N.+3 cc. TEL 98. 2 97. 4 90.1 430 F.+, Vol. Percent 9. 4 23. 6 35. 4 62. 3

1 Carbon may be high due to oil retained in feed and product lines at end of crack cycle.

The addition of boria to the cobaltmolybd'ate on alumina catalyst greatly increases its hydrocracking activity. This is best illustrated in columns 2 and 3 above, wherea slight-- 1y higher 430 F. conversion was obtained at a lower temperature and a higher space velocity with the boria promoted catalyst.

The above data show that hydrocracking of colcer gas oil over the boria promoted cobalt molybdate on alumina catalyst produces a low sulfur gasoline of satisfactory I octane number with selectivity equivalent to that obtained I pp that the selectivity to Carbon and y 5' bycatalytic cracking. The selectivity to gasoline is higl forthe two Qatalysts WOuld h abollt Same at q or at the lower conversion obtained by the catalyst withlent cohvefsloh- The horla'cohtalhlhg Q y makes out the boria but the octane number is considerably more C and probably less C 430 F., at equivalent conlower. version. However, the gasoline pro'ducedha's a consid- EXAMPLE 4 erably higher; octane number 97.4 vs. 90.1 RON+3 cc. 7

TEL, and a higher front end volatility than that from co- Addlhonal P were made Whlch further balt molybdate alumina catalyst, onstrate the superiority of the cobalt molybdate-boria- Both of the catalysts were satisfactory for reducing alumina catalyst of the Present invention Over a the sulfur and nitrogen of the coker gas oil. mercial catalyst with about 3% C00 and 10% M00 5 Feed, Total Products.

05-430" F. 430 F.+ Fraction S, Wt. 'N2,Wt.

Per- Percent cent S, Wt. N2,Wt. S, Wt N2,Wt.

Per- Per- Per- Percent cent cent cent Once through catalytic cracking of the Tia Juana coker gas oil over equilibrium silica-alumina cracking catalyst gave 34.0 vol. percent C -430 F. at 44.9% 430 F. conon an alumina base and the same catalyst pretreated with hydrogen sulfide. The results obtained are summarized in Table V.

Table V 900 F., 3000 P.S.I.G., 1 V./V./HR.. 6000 S.C.F. Hz/B., RAW SHALE OIL FEED RUNS LENGTHS: 145-185 HRS.

Commercial Sulfided Catalyst CoMo0 :BO :AliO; CoMoO Commercial A120; CoMoOr:

Conversion (430 F.), Vol. Percent 81 73 64 Yields:

Dry Gas (Ci-Ca), Wt. Percent .22 16 13 C4, Wt. Percent 11 6 5 (l -430 F., Vol. Percent..- 60 64 .62 vCarbon, Wt. Percent 0.15 0.12 0.10 Naphtha Quality:

Gm vity. API 54. 5 55. 2 55.0 Bromine Number 12 9 7 Research 0.N., Clear 60.1 49.6 44.0 Research O.N.+3 00. 78. 7 71. 5 68. 7 11. 70 11. 74 11. 82

Hydroformate (Estimated) 54 .50

1 Run on 65 430" F. traction as cut at stills. 9 200/370 F. fraction.

version. A comparison of the gasoline selectivity and quality from this run and the more favorable hydrocracking results from each of the above catalysts is shown in Table IV.

These runs again show the greater activity of the cobalt molybdate-boria-alumia catalysts and the substantially higher octane number of the gasoline product obtained therewith. While the octane number of the product is of course very loW by modern gasoline anti-knock standards, the K factor (Watson characterization factor) of the 200/ 370 F. fraction indicates that this product may be more readily hydroformed to high octane number products.

number product as noted.

Example 5 A cobalt molybdate on alumina catalyst and similar catalyst which contained 10% boria were compared in the hydrocracking of a 70% shale oil distillate. The hydrocracking was effected at 800 p.s.i.g. and with 5000 s.c.f./b. of hydrogen. I

suits are summarized in Table VI.

This advantage is indicated by the higher w./hr./w. allowable when hydroforrning to a octane The temperature and space velocity were varied for the requiredconversion. The reassume;

Table VI CoMO4: A1203 Catalyst 77 Vol. Percent 430 OoMoOuAlzOazBzO:

F. Conv Yields:

Carbon Wt. Percent. C Wt. Percent..

(Jr-430 F., Vol. Pcrcent Inspections:

Gasoline, R.O.N.+3 cc Gas Oil, Wt. Percent N2..-

ram

EXAMPLE 6 In view ofv the poor properties of raw shale oil as a cracking or hydrocracking feed stock, raw shale oil was subjected to solvent precipitation and the treated shale oil subjected to hydrocracking with the catalyst in accordance with the present invention.

In one case, one volume of raw shale oil was added slowly to three volumes of n-hexane with rapid stirring. The mixture was allowed to stand at room temperature overnight. The liquid phase was then decanted and the precipitate or sludge was washed with four portions of nhexane and the washings combined with the decanted liquid phase and the resultant mixture was stripped of solvent to give an improved shale oil feed stock in about 95% yield.

In another case the mixture of raw shale oil and solvent was saturated with an acidic reagent to further improve the shale oil feed. Hydrogen chloride was used as the acidic reagent but other acidic materials such as hydrogen bromide, sulfuric acid, sulfur trioxide, boron trifiuoride or the like may be used. The resultant mixture was allowed to stand overnight, the liquid phase decanted, the precipitate or sludge was washed and the solvent then was removed from the treated shale oil.

The thus improved shale oil feeds were subjected to hydrocracking with a cobalt molybdate-alumina-boria catalyst in accordance with the present invention. Reaction conditions were 900 F., 700 p.s.i.'g., 1. v./v./hr. and 5000 c.f.H /b. The results are summarized in Table VII.

The advantage for adding boria to catalysts of other compositions is illustrated in the following examples. Catalyst J was prepared by impregnating 10% B 0 as H30 on catalyst K which was made by impregnating an alumina from aluminum alcoholate with ammonium molybdate and cobalt acetate to give 15 Cob I00 Catalyst L was prepared by impregnating 10% B 0 as HBO on Catalyst M which was made by impregnating 15% CoMoQ; as ammonium molybdate and cobalt acetate on a base of zinc-aluminate spinel. Catalyst N was prepared by impregnating Catalyst H in Example 2 consisting of 20% boria on alcoholate. alumina with ammonium molybdate and cobalt acetate to give 15% Col/I00 Catalyst 0 was prepared from the same base as catalyst N but was impregnated with ammonium molybdate and nickel nitrate to give 15% .NiM oO Test results ob= tained on these'catalysts under the same conditions as Example 1 are summarized in Table VIII.

Table VIII Catalyst J K L M N 0 1 P 23:3? 1 3 E9 .3 Y "i 66 61 46 45, 67 76 Y! Ids.

(ll-400" F. Vol. Percent 63 51 47 42 57 54 (la-Ga I4 19 '7 10 19 27 Carbon, Wt. Percent 4. 9 3. 3 4. 1 3. 8 7. 3 7. 8 Wt. Percent Nitrogen in 400 The addition of boria in each case is shown to give a more active catalyst with greater removal of nitrogen as measured by the nitrogen content of the 400 F.-|- product.

EXAMPLE 8 An advantage forboria containing catalyst is also illustrated by the following data obtained with the 70% distillate fraction from raw shale oil under mild conditions of 800 F. temperature, 800 p.s.i.g. pressure, 1 v./v./hr. feed rate for 3 hours. Under these milder conditions the product desired is principally a low nitrogen gas oil for further processing as in conventional catalytic cracking. The boria containing catalyst P used in this example was prepared by mulling boric acid with an alumina trihydrate slurry obtained'from aluminum alcoholate and impregnating the dried alumina-boria base with ammonium molybdate, cobalt acetate and nickel acetate to give the composition 3.5% B 0 9% M00 2.7% C00 0.3 Ni() and 84.5% A1 0 Results obtained with this catalyst are compared in Table IX with data for a catalyst of composition 15 CoMoO on alcoholate alumina similar to catalyst K.

At the same conversion, catalyst P shows less carbon production and less nitrogen in the 400 F.+ product.

EXAMPLE 9 A catalyst consisting of 10% boria on a commercial molybdena hydroforming catalyst containing about 10% molybdena on a silica stabilized alumina was prepared by impregnating the hydroforming catalyst with a boric acid solution. This composition is an active hydrocracking catalyst for such feeds as shale oil and coker gas oil.

The foregoing description contains a limited number of embodiments of the present invention. It will be understood that numerous variations are possible without departing from the scope of this invention.

What is claimed is:

1. A process of hydrocracking refractory hydrocarbon mixtures selected from the group consisting of raw shale oil, raw shale oil distillates, and coker gas oil and having an initial boiling point of about 350 F. or higher and the end point above about 800 F.,.which comprises contacting said refractory hydrocarbon mixture in admixture with hydrogen with a catalyst containing 5 to 20 wt. percent molybdenum oxide, 0-6 wt. percent nickel oxide, 06 wt. percent cobalt oxide, 4-16 wt. percent boria, 0-10 wt, percent silica and the remainder alumina, at a temperature of about 900 F. to 1000 F. under a pressure of to 1000 p.s.i.g., with a hydrogen gas rate of about 1000 to 10,000 cu, ft. per barrel of the hydrocarbon mixture feed for a period sufiicient to convert said feed, including a yield of C to 430 F. gasoline which is in major proportion in volume percent to the feed.

2. A process as defined in claim 1, in which the refractory hydrocarbon mixture feed contains 0.2 to 4 wt. percent of sulfur.

3. The process as defined in claim 1, in which the refractory hydrocarbon mixture feed is a shale oil containing about 1-3 wt. percent nitrogen and about 0.2 to 1.5 wt. percent sulfur.

4. The process as defined in claim 1, in which the catalyst contains molybdenum oxide and cobalt oxide as cobalt molybdate on an alumina-boria support.

5. A process of hydrocracking a shale oil boiling in the range of about 350 F. to about 800 F. which comprises contacting said shale oil as feed stock mixed with hydrogen with a catalyst containing 5-20 wt. percent of cobalt molybdate on an alumina-boria support containing 80-95 wt. percent of alumina and 5-20 wt. percent boron oxide at a temperature in the range of about 900 F. to 1000 F., under a pressure of 100 to 1000 p.s.i.g., said hydrogen being mixed with the feed stock at a rate of 1000 to 10,000 cu. ft. per barrel of said feed stock,

tion yield which is more than volume percent based on the feed stock. a

7. A process as defined in claim 5 in which the shale oil feed stock is a shale oil distillate, and in which the products boiling below 430 F. include a C 430 F. fraction which is a major volume proportion to the feed stock.

References Cited in the file of this patent UNITED STATES PATENTS 2,692,226 Smith Oct. 19, 1954 2,878,180 Watkins Mar. 17, 1959 2,880,171 Flinn et al. Mar. 31, 1959 2,882,221 Dinwiddie et al. Apr. 14, 1959 2,911,356 Hanson Nov. 3, 1959 

5. A PROCESS OF HYDROCRACKING A SHALE OIL BOILING IN THE RANGE OF ABOUT 350*F. TO ABOUT 800*F. WHICH COMPRISES CONTACTING SAID SHALE OIL AS FEED STOCK MIXED WITH HYDROGEN WITH A CATALYST CONTAINING 5-20 WT. PERCENT OF COBALT MOLYBDATE ON AN ALUMINA-BORIA SUPPORT CONTAINING 80-95 WT. PERCENT OF ALUMINA AND 5-20 WT. PERCENT BORON OXIDE AT A TEMPERATURE IN THE RANGE OF ABOUT 900* F. TO 1000*F., UNDER A PRESSURE OF 100 TO 1000 P.S.I.G., SAID HYDROGEN BEING MIXED WITH THE FEED STOCK AT A RATE OF 1000 TO 10,000 CU FT. PER BARREL OF SAID FEED STOCK FOR A PERIOD SUFFICIENT TO CONVERT A MAJOR PROPORTION OF SAID FEED STOCK TO PRODUCTS BOILING BELOW 400*F. 